1. Field of the Invention
The present invention relates to an image forming optical system and an electronic image pickup apparatus using the same.
2. Description of the Related Art
As a zoom lens system for an image pickup apparatus with a high zooming ratio, in which, an image pickup element of a large number of pixels is used, zoom lens systems described in Japanese Patent Application Laid-open Publication Nos. 2007-298555, 2006-349947, and 2007-163964 are available. The zoom lens systems in these reference patent literatures have a cemented lens in a first lens group. Moreover, the cemented lens has a sandwich structure in which, a resin having a specific partial dispersion ratio and Abbe's number is sandwiched.